Automatic coal stoker



m5151945 G. E. mmm mi. 2,204,555

AUTOMATIC COAL STOKER Filed Nov. 2o, 1959 s sheets-sheet 2 ATTORNEYS s. E. VALENTINE x-:r AL v2,204,555

`UTMAI'IC COAL STOKER med mw. 2o. 1959 s sheets-sheet s lNvEm'on ATTORNEYS June 18, 1940.

Patented June 18, 1940 UNITED STATES AUTOMATIC COAL STOKER `George E. Valentine and John I. Hurst, Schuylkill Haven, Pa.

Application November 20, 1939, Serial No. 305,342

1 Claim.

This invention relates to automatic coal stokers and has for an object to provide in a device of this character an inclined grate having per- `forations .of greater dimension at the bottom 5 than at the top through which a forced' draft may be blown to more effectively promote combustion than in similar devices.

A further object is to provide apparatus of this 4type including a notched step actuated roll at m the bottom of the grate for removing ashes and also for preventing co'al from sliding off the grate so that a uniform coal bed will be effected.

A further object is to provide apparatus of l5 this type having a step actuated pusher head which-may be adjusted to feed the fuel at any pre-determinedv rate so that more uniform combustion will be obtained than hitherto possible. A further object is to provide apparatusof this character having a pipe for carrying away .obnoxious fumes and also to enable the apparatus to hold the re when the motor is not running.

A further object is to provide apparatus of this character which will be .formed of a few strong simple and durable parts. which will be inexpensive to manufacture, and which will not easily get out of order.

With the above and other objects in view the invention consists of certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood that various modifications may be resorted to within the scope of the appended claims withoutv departing from the spirit or sacrificing -any of the advantages of the invention. In Ithe accompanying drawings forming part of this specification:

Figure 1 is alongitudinal sectional view, with parts in elevation, of an automatic coal stoker constructed in -accordance with the invention.

Figure 2 is a plan view of the apparatus shown in Figure l, with the boiler, hopper andfume pipe Y removed.'

Figure 3 is a side elevation of the stoker show- 4 1 ing the ratchet drive for the pusher head and notched roll. y

Figurel 4 is a plan view of the grate. l

Figure 5 is a side elevation of the driving disk and wrist pin. y

50 Figure 6 is a cross' sectional view of the disk shown in Figure 5. l

Figure 'i isa cross sectional view taken on the line 'I-l of Figure 3.

Referring now to the drawingsin which like 5.5 characters of reference designate similar parts` (or 11o-109) in the various views, a preferred embodiment of the invention is shown, in which I designates a box-like base of substantially rectangular contour having an integral shelf I I braced by legs i3 at the rear of the base. and supporting the main operating units, namely, an electric motor I2, a fan i3, and a speed reduction unit I4, these parts being conventional. The base also serves as an ash pit and is` provided with an opening I and door I6 in the front for the removal of ashes. lo

Thetop portion of the base is adapted to support a cylindrical iirebox I1 which' is provided with an inclined grate support I8 on the inside and with a pusher box I9 on the outside, both preferably being formed integral with the rel5 box. A fuel supply hopper 9 is mounted on the top of the pusher box.

The grate is disposed between the side members 2l of the grate support, both the grate and the chute being mounted at an appropriate angle 20 to the horizontal to facilitate movement of the coal downward over the grate, as best shown in Figure 4. 'I'he grate is provided with a plurality of air ports 22, and thehead end 23 ofthe. grate is curved and beveled so as to make a closet against the curved surface of the inside of thel iirebox. 'I'he head end of the grate rests upon a ledge 24 formed .integral with the firebox and likewise the foot or lower end 25 of the 'grate rests upon a ledge 26 formed integral with the 30 grate support i8. While the grate is shown as consisting of a single unit it is understood that it may be made in sections for the larger sizes of stokers. The front of the rebox is provided with an extension 21 and with a door 28 for 35 kindling, cleaning and inspection.

It will be seen by referring to Figures l and 2 that the fan I3 is provided with an outlet pipe 28 which enters the wall of the-rebox underneath the grate to direct a forced draft upwardly through thel grate to promote combustion. The fan is also provided with an adjustable circular baule disk Il at the intake opening to permit adjustment` of the'air supply.

A conventionalvertical type due boiler Il is 'mounted on top oi' the nre box l1 but other types obnoxious fumes that may result from the use o! wet fuel. This fume pipe is equippedwith a damper 35 to permit combustion being controlled when the motorfis not running. u

A notched roll 36 is mounted on a step driven shaft 31 which is journalled in bearings in the base |||l at the bottomof the grate support. 'I'he roll is driven .at a pre-determined rate of speed to removeashes, and projects to about the same height as the side members 2| of the grate suphigh speed of the motor I2 and imparts slow speedA t'o the final shaft 39 ofthe reduction gear train. The shaft36 is equipped lwith a crank disk 46, best shown in Figures 5 and 6.

. The crank disk 40 is provided with a slot 4| which extends from the hub 42 to the-periphery of the disk. An H block 43 is mounted in the slot and is provided with a threaded, opening to re- Aceive an adjusting screw 44 which is uniformly reduced at its innerrend as shown at 45 to receive a plunger 4,6 mounted in an opening 41 in the hub. A helical spring 48 is conned in the opening back of the plunger by va screw 46. By turning the adjusting screw 44 the throw of the crank pin 50 carried by the block may be'varied.

A rock' shaft 5| is journaled in the sides.` of the pusher box and, is provided inside the box with a pair of rocker arms 52. The shaft is provided 1 outside the pusher box with a rocker arm 53. A fuel pusher, in. the nature of a thick plate 54, is disposed transversely of the pusher box and rests upon the bottom thereof adjacent to the top of the grate 20. The fuel pusher is connected to the rocker arms 52 by a pair of rods 55.

A rocker arm 56, best shown in Figure '7, is mounted upon a sleeve 51 which is secured by a set screw 56 to a boss formed on the base I0 and forms a `bearing for the rachet wheel shaft 31. 'I'he rocker arm carries a pawl 59 which engages the teeth of the ratchet wheel 38 toimpartZ step motion through the ratchet wheel to the notched roll 36 at the bottom of the grate.

The crank pin 56 of the crank disk 46 and the outerV end of the rocker arm 56 are connectedv together by a link 60 to permit the rachet wheel being driven by the crank disk. A link 6|' connects the rocker arm 53 which is outside the pusher box I9, with the rocker arm 56. A single pin 51 is shown 'as connecting the links 66 and 6| to theA rocker arm 56'and this pinvforms a pivot for the pawl 59. When the rachet wheel is driven by the crank disk, the link 6| imparts step motion to the. fuel pusher 54 and simultaneously the fuel to move down lover the grate.

` will be ratchet wheel imparts step motion tothe notched roller 36,.

A baille plate 62 is adjustably mounted on the front wall of the pusher box by adjusting screws 63 passed through slots 64 in the plate and engaged in the front wall of the pusher box. The baille plate regulates the depth of the fuel bed at the top of the grate. v

In operation the fan delivers a current of airto the compartment in the basevunder the grate 26 and through the tapered air ports 22 in the grate to produce a forced draft through the coal bed. The motor imparts motion through the speed reduction unit I4. to the crank disk 40, crank pin 56, and through the link 60 to the rocker arm 56 and paw] 59. Forward motion of the pawl imparts motion to the ratchet wheel 38, shaft 31 and notched roll 36. On its forward` motion the pawl also imparts movement through the link 6| to the rocker 56, pair of rods 55 to the fuel pusher 54. Thelatter urges` a small quantity of At a certain pre-determined temperature a thermostat (not shown) stops the motor for a period that may have considerable range and thn starts the motor again, thus. promoting economy in electric current as well as fuel.

From the above description it is thought that the construction and operation of the invention fully understood without further explanaf tion. What is claimed is:

A coal stoker comprising the combination with\ a fire box, of a base supporting the vfire box forming any ash pit, a grate in'l the ilre box sloping downwardly from the rear of the fire box to the base, a pusher box extending in alinement with the grate on the rear of the re box, a hopper` communicating with the pusher box, a notched roll supported by the base at the `bottom of the grate and extending above the grate for preventin'g coal from sliding off the grate, a reciprocatory pusher in the pusher box for feeding coal from the hopper onto the grate, means for effecting a forced draft upwardly through the grate, a ratch-4 et wheel connected to the notched roll, an electric motor, a speed-reduction unit connected to the motor, a crank disk connected to the unit having an adjustable wrist pin, a link' connected to the wrist pin, a pawl connected to the link and engaging the ratchet wheelv for imparting step rotation to the ratchet wheel, a second link connected to the flrst named link andv extending upwardly therefrom, and a-'crank connecting the second named link with the-pusher for reciprocating the pusher.

.GEORGE E. VALENTINE.

"J. I. HURST. 

